This invention relates to methods for discriminating between types of electrical appliances connectable to a supplementary device, such as a charging, cleaning and/or diagnosis device for a small electric device, such as an electric hair cutting or hair removal apparatus or an electric toothbrush.
A method for transmitting data between a small electric device, such as an electric hair cutting apparatus, an electric toothbrush or a domestic appliance, and an electric supplementary device, such as a charging, cleaning or diagnosis device designed to be connected to it, is described along with accordingly designed devices in DE 198 17 273. Data is transmitted along electric and/or magnetic routes, e.g., in the case of a small electric device equipped with a power socket via the electric power socket and in the case of a small electric device powered by a primary battery via the battery contacts. The transmission of data is also understood to mean the transmission of control commands which, issued from the supplementary device for example, can activate particular functions of the small electric device. If, for example, the small electric device is an electric shaving apparatus and the supplementary device a cleaning device for the shaving apparatus, such as is described in DE 44 02 236 A1, it will be possible, for example, for the cleaning device to switch the shaving apparatus on and off at the correct moment in the cleaning cycle and also, where required, to charge a storage battery accommodated in the shaving apparatus.
From DE 196 06 719 C2 there is known an electric shaving apparatus having a controller capable of issuing a signal indicative of the need to clean the shaving apparatus, and a cleaning device for a shaving apparatus which simultaneously acts as a holder for the shaving apparatus. When the shaving apparatus is inserted in the cleaning device, the controller can be connected via the mains contact of the shaving apparatus to the cleaning device in such a way that a transmission of signals between the shaving apparatus and the cleaning device is possible. To prevent the cleaning device from performing a cleaning operation unnecessarily each time the shaving apparatus is placed back in its holder, the cleaning device is activated only when the controller sends a corresponding signal to the cleaning device. Hence a shaving apparatus which has no controller to issue a cleaning signal cannot be cleaned in this cleaning device.
It is therefore an object of the present invention to provide a supplementary device for a small electric device which is also capable of interacting with small electric devices lacking a controller.
To accomplish this object, a supplementary device, such as a charging, cleaning and/or diagnosis device, is provided with at least one connection via which it is electrically and/or magnetically connectable to the small electric device, such as an electric hair cutting or hair removal apparatus, particularly an electric shaving apparatus, or an electric toothbrush. With the detection arrangement the supplementary device can automatically identify whether it is connected to a small electric device, thus making it unnecessary for the small electric device to issue a signal or for the user to operate a switch or some other actuator. User friendliness is thus increased and maloperation ruled out. Furthermore, the actuator otherwise needed on the device can be omitted, resulting in a notable cost advantage.
A particularly simple detection arrangement monitors an electric and/or magnetic quantity prevailing at the connection of the supplementary device. In the case of an electric connection involving at least two terminals, for example, the electric resistance or the voltage between the terminals will vary when the devices are connected or disconnected. The same applies likewise to a magnetic or electromagnetic connection. If the electric and/or magnetic quantity varies by more than a certain minimum amount from, for example, the state existing when no small electric device is connected to the supplementary device, then the detection arrangement will issue a corresponding signal indicating that the devices are connected. Preferably, however, the detection arrangement does not evaluate the variation of the electric and/or magnetic quantity but includes a comparator which compares the electric and/or magnetic quantity with at least one reference value. If the electric and/or magnetic quantity residing at the connection is of an amount lying below the reference value, for example, the small electric device is connected to the supplementary device and vice versa.
According to a preferred further aspect of the present invention, the detection arrangement is also capable of establishing the particular type of small electric device connected to the supplementary device. For this purpose a supplementary device of the present invention can be connected via a further terminal to the small electric device and includes, for example, a microcontroller which connects a signal source, particularly a voltage source, to said terminal via a switch controllable by the microcontroller: either a first or a second type of device is connected to the supplementary device depending on whether the electric and/or magnetic quantity between the two other terminals then changes.
If, for example, the supplementary device is a cleaning and charging device for shaving apparatuses which operates on the basis of the cleaning program known from DE 44 02 236 A1, which involves switching on and off of the shaving apparatus while being cleaned by the supplementary device in order to achieve an optimal cleaning effect, then the cleaning and charging device must be able to detect, for example, whether the connected shaving apparatus contains a storage battery or not. In the case of a shaver with a built-in storage battery and a motor able to draw current only from the storage battery, it may first be necessary to charge the storage battery before the cleaning program can be executed. By contrast, shavers without a storage battery are supplied with electricity directly from the cleaning device during cleaning.
In a further aspect the supplementary device includes several comparators which compare the electric and/or magnetic quantity present at the two terminals of the supplementary device with several reference values. Depending on between which reference values the electric and/or magnetic quantity lies, either a particular type of small electric device or no small electric device is connected to the supplementary device.
The present invention will be explained in the following with reference to a cleaning device and an electric shaving apparatus as an embodiment for a supplementary device and a small electric device illustrated in the accompanying drawing. Further embodiments are dealt with in the description.